This is a continuation application for HL-19185 Pulmonary SCOR: Neonatal Respiratory Distress Syndromes. It entails an interdisciplinary approach to research on: 1) the causes, prediction, prevention, diagnosis, early and late treatment, and long-term followup of respiratory distress syndromes of the newborn, especially hyaline membrane disease; 2) the development of the lung in the fetus and newborn, with special reference to the surfactant system, to factors determining fluid distribution in the lungs, and to hormonal mechanisms in lung maturation.